Second Year Summary – Planting, Dan DeLago 2016

Minimizing tillage and attempting to provide constant cover for the soil via intercropping

were two major goals in the spring. In this passage I will discuss the various techniques

applied to achieve these goals and potential improvements for the future.

2015

A chisel plow, discs and roto-tiller were applied to prepare ground for fall cover crop

blocks. These were seeded with a mix of winter legumes and grasses. A potential improvement to this method of whole field tillage would be pasture cropping. Colin Seis’s operation near Sydney, Australia has developed this operation which integrates perennial crop mixes with intensive rotational grazing. This method requires several years between vegetable crops. However, between vegetable crops pastured ruminants and grain crops are harvested.

Attempts to reduce tillage heading into winter included broadcasting cover crop mix on production blocks cleaned of debris from previous flower and tomato crops. Compost applied via compost spreader covered the seeds. Germination was good in these trials and the cover crop stand was relatively free of unwanted plants. In November, garlic was planted in the furrows which previously grew tomatoes. Through this method, one round of soil preparation served two crops. The garlic bulbs were covered with 6”+ of straw. A modification of this approach would be to intercrop with several species of clover to feed the crop and provide ample shade for the soil surface during spring.

2016

In March, a mix of roots and peas were planted in raised beds. As the previous winter crops were harvested, bare soil was left. With brief hand weeding the beds were prepped and seeded without tillage and a robust crop of sugar snap peas was reaped by early May. Maintaining constant soil cover on beds being harvested in late fall can be difficult as conditions do not favor planting cover crop. To prevent winter erosion, I would personally suggest experimenting with some form of mulching. We experimented with sheet mulching this year to decent success. This included layers of manure (green or ruminant), sheets of cardboard, a very shallow layer of compost to breakdown the carbon rich mulch, and wood chips. When inoculated with King Strophoria (Garden Giant) mushroom spawn, a good yield of fungus can be harvested in spring and fall. A simpler method would be covering production areas with leaves and layers of old hay toprevent leaves from blowing away.

As the annual rains reduced our ability to do tractor work in the majority of the operation, preparing raised beds for mid April planting relied heavily on tillage to breakdown mature cover crop residue. Planting into thicker residue was the result. An improvement to our practices would be to plant raised beds with winter kill cover crops. Incorporating winter kill legumes, oats and other green manures may allow for reduction or elimination of fertilizer input. I am personally a big fan of broad forking as a means of ensuring soil aeration. However, it does take a significant amount of time and energy. During May, the decomposing residue retained moisture despite a lack of rain and it was clear that the crops were very healthy. As day temperatures began to exceed 85 degrees, we experimented with solarization; using “waste” pieces of greenhouse plastic. Beds were mowed and solarized, effectively killing all residue. We would then till the residue and plant. A modification of this technique to prevent tillage would be inserting transplants directly into the crop residue. In experimental plots we tried inserting transplants directly into solarized soils aerated with the action of the broad fork. This worked well. Direct seeding is more difficult as the hand seeders are unable to breakthrough residue. BCS attachments capable of crimping residue, cutting residue, and jab planting seeds would make direct seeding into solarized or crimped cover crop easier for small scale operations.

As the season progressed, the solarization technique was useful for rapidly turning over crop residue, but the rear tine tiller was still employed for every preparation. Our typical method of field bed preparation included ripping a 12” deep furrow with the IH 140, compost and fertilizer application, followed by several rounds of tillage with the Case 265 – 36” tiller attachment and/or 18” BCS rear tine tiller attachment. Modifications to these practices would be the implementation of a rotary power harrow for both walk behind and tractor attachment. The rotary power harrow horizontally mixes the soil surface without pulling unwanted seeds up from deeper depths. For late germinating crops (beets and carrots), a flame weeder was applied about 5-7 days after seeding. Occulation with an opaque fabric after tillage encourages germination of weeds, especially when soil moisture is scarce. It would also be interesting to determine if occulation after tillage prevents carbon dioxide from leaching into the atmosphere. Compost is traditionally covered to prevent nutrient release into the atmosphere so the same principle should apply… in theory. Although the techniques listed above to reduce tillage were fairly effective, the application on a large scale is difficult to envision without the use of tractor implements or grazing ruminants. The key line plow has been developed for deep soil aeration and can/has been combined with a seed drill, fertilizer applicator and compost tea applicator to jumpstart soil health on degraded and compacted land. Seeding a diverse crop including grasses, legumes, mustards, brassicas, roots, chenopods, herbs and dynamic accumulators would be beneficial for feeding soil, especially if combined with intensive rotational grazing techniques.

I was interested in experimenting with intercropping in the beginning of the season as a means of providing constant soil cover to reduce evaporation of soil moisture. Our cover cropping techniques included hand broadcasting a cocktail of buckwheat, vetch, peas, clover and wheat after tillage of pathways. This typically occurred when the next production block was maturing. In this fashion, we could mow the flowering cover crop after harvesting had ceased. Another method for cropping pathways was simply spreading clover seed before mowing. This technique allowed mineral rich plants such as plantain, burdock, dandelion and chicory to act as a nurse crop for the legume seed.

Intercropping using polycultures seems to be an effective means of maximizing space. I have personally been experimenting with the meso-american polyculture of corn, beans and squash for 5 years. Traditionally these milpa systems produced a wide variety of plants in addition to the three sisters (ie. sweet potatoes, chiles, tomatillos, melons, flowers, leafy greens, herbs, small grains, young trees etc). Complementary architectures of both foliage and roots, allows for satisfactory distribution of nutrients, moisture and light. The diversity of root exudates further enhances soil biology. Granted it would be very inefficient for a farm paying people to stumble through a corn jungle to harvest melons, but complex polycultures should be common place in cover crops.

Over the course of the year, I realized that my goal in pursuing a career in regenerative agriculture was to develop a holistic understanding of the watershed services of farmland and to find the most effective strategies for protecting our living waters. Rain water infiltration, percolation and purification through topsoil formation should be one of the primary goals for all farmers. The improved health of terrestrial and aquatic ecosystems, better food and water quality, the growth of economic assets (topsoil and water) and an effective strategy for fighting climate change/desertification are a few of the benefits of building soil. Learning the on ground application of retaining rain water in soils was a major motivator for myself in hindsight. In this essay I will discuss the importance of eliminating tillage, building soil organic matter and maintaining soil cover as it relates to the health of watersheds.

Soil organic matter (SOM) is oxidized through tillage and therefor released into the atmosphere as greenhouse gases at various concentrations relative to different tillage operations (Al-Kaisi and Yin, 2005). Because soil organic matter absorbs moisture like a sponge, up to 20 times its weight in water, eliminating tillage improves the water and nutrient uptake efficiency of plants (Johnson et al., 2005). The water retention capability of SOM plays a crucial role in the health of our watersheds. Percolation allows for a prolonged release of freshwater into our creeks, streams and estuaries without the deposition of sediment, which all too often results in eutrophication and marine dead zones; a huge problem for marine ecology (ie: the Gulf of Mexico).

Gabe Brown of North Dakota has seen a 250-300% increase in soil organic matter, a 16 fold increase in water infiltration (1/2”/hr to 6”/hr) and 90% reduction in fertilizer application using no-till and intensive rotational grazing techniques (extension.psu.edu, 2014). Using very diverse cover crop mixes, as proven by Dr.Ademir Calegari, the Brown’s crop and rangeland remain constantly covered. With constant cover the temperature of the soil never gets so high as to affect soil microbiology or evaporation/transpiration rates of the crops (Chavez NRCS 2010).

Another piece of research to mention in regards to the prevention of eutrophication is STRIPS (Science-Based Trials of Row-crops Integrated with Prairie Strips). STRIPS can have a major impact in reducing erosion and nutrient leaching. STRIPS researchers concluded that if 10% of a production field was converted to native prairie strips nitrogen loss was reduced by 80%, phosphorous by 90% and sediment loss by 95% (5,000 lbs of soil/acre) (Dell-Harro, 2015). The benefits of having living roots in the soil and carbon covering it are numerous. In the end, I hope this essay expresses the holistic value of living soils as they relate to our crop land, watersheds and marine waters.